How Mobile and Tower Cranes Are Assembled & Dismantled

Mobile cranes come in many styles, shapes, and sizes, with the hydraulic crane and the luffing jib being the most common. R. Baker & Son has worked with just about every mobile crane on the market. Some are so large that assembling them requires multiple tractor trailers of booms and hardware, along with several smaller cranes to help put the main crane together. And of course, it takes a skilled team of riggers to assemble and later dismantle a crane that may only be needed for a single lift.

However, mobile cranes can't reach the heights or scale required to build tall buildings safely and efficiently. That's where stationary cranes come in, falling into two basic categories: internal and external. Within these, there are two primary crane types to choose from: the hammerhead crane, with its vertical mast, horizontal jib, and counterweights, and the luffing jib crane, which angles upward much like a fishing pole and also relies on counterweights. R. Baker & Son has worked with many tower crane systems as well.

Choosing the right crane depends on several factors, including the maximum weight to be lifted, the crane's overall reach, the height of the building, and how many picks are needed per day or per hour. These requirements may point to using a single crane or several, depending on the size of the project, the surrounding site conditions, and any obstacles that need to be worked around.

Let's start with what's needed to install an external crane, since these are the most common. Once the structural engineering team carefully selects the right crane for the project, erecting and eventually dismantling it involves several key steps. Here's a concise overview of the process:

Erecting an Exterior Crane

Base Installation: A substantial concrete foundation is prepared to support the crane's weight and stability. The base frame is then placed on the foundation and secured, typically with large bolts deeply embedded into the concrete.

Bracing: The crane is stabilized with diagonal braces attached to the base and the tower sections. These specifically designed and engineered braces provide lateral support, preventing swaying and ensuring structural integrity as the crane rises.

Raising the Tower: The crane operator uses a climbing frame to incrementally raise the tower. Additional sections are added through a process called "jumping," where hydraulic jacks lift the tower so new sections can be inserted underneath and connected safely by experienced riggers like R. Baker & Son.

Dismantling the Crane

Lowering the Tower: Dismantling begins by carefully removing the top components, including the jib, or horizontal arm, and the counterweights, in a specific sequence so the crane does not tip. Hydraulic jacks then lower the crane back down to its original height.

Removing Sections: Once lowered, the tower sections are taken apart in reverse order of assembly, with each section carefully removed and lowered to the ground.

Base Removal: Finally, the base is unbolted from the concrete foundation, and any remaining components are cleared from the site.

Internal Tower Cranes

Internal tower cranes take a somewhat different approach, since they don't have access to the jumping method used by exterior cranes. Instead, they operate by lifting or sliding up within an elevator shaft or other vertical opening, bracing, then lifting, achieving the same goal by a different method.

Installing an internal tower crane also requires a substantial concrete foundation with embedded bolts. The base is located strategically within an elevator shaft or similar vertical opening, and is connected to the concrete foundation. Several vertical sections are then installed, followed by the crane's cab, jib, and counterweights, all mounted carefully on top, using a smaller crane, of course.

As the building rises beyond several stories, the crane rises with it using a pair of cross-member braces that slide through the shaft wall and rest on the concrete floors. Once secured and checked by the riggers, the crane is hydraulically lifted to the next story, then braced by additional supports within the shaft. Essentially, the crane climbs and supports itself on each floor, then lifts itself to the next level.

Removing an internal tower crane can be done by several methods, though the most common involves the tower crane lifting a smaller crane, called a derrick, to the roof and mounting it to a specifically designed steel dunnage support. Once the derrick is in place, it begins dismantling the jib, counterweights, and cab. Once those are removed, the derrick lifts each vertical section out of the elevator shaft until the base section is removed and lowered to the ground outside the building.

Once that's complete, the derrick removes most of its own structure, and what remains is taken down the elevator or shaft to ground level.

Founded in 1935, R. Baker & Son All Industrial Services is a certified Minority and Women-Owned Business Enterprise (M/WBE) - recognized as the oldest and largest M/WBE-certified demolition contractor in North America. We are your trusted partner for complex industrial and construction projects, specializing in heavy rigging, machinery moving, plant relocation, and expert crane erection, dismantling, and support services across the United States, Canada, and Puerto Rico.

With significant bonding capacity and an unmatched safety record backed by extensive involvement in OSHA VPP Star projects, we deliver precision and reliability to every job site. Our comprehensive services include heavy rigging, complex machinery installation and removal, plant relocation, industrial dismantling, and specialized support for high-reach and tower crane operations.

Discover why leading industrial and commercial clients rely on R. Baker & Son for safe, precise solutions to their most demanding heavy rigging and dismantling projects. Learn more about our expertise in industrial rigging and complex plant relocation.